I was going to be very harsh on this until I realized it's a demo. For that, I would still say it's not very useful as is, even though a couple of interesting things were attempted. First, we have the map of the city as the loading screen. That doesn't make any sense. You are given no objectives, and the objective screens were edited to be very confusing. If you don't read the mission notes, you won't have a clue what is going on. I clicked a floating skull and had no idea what it did. Many don't like reading mission notes ahead of time, as they tend to spoil things, so if it's not clear in the map, consider that it will confuse some players.

While these things were strange and nonsensical in the mission, I can see the value of learning how to do them for a more sensible purpose. For the combat, you are sword-fighting green things that look pretty bad (and are just ratmen ai and voices) and take anywhere from 4 - 6 overhead (power) swings to kill. It's a very short and linear mission with nothing to look at along the way. I honestly couldn't find a reason to try again with the other "classes" as the mission just didn't offer anything, but I wonder if there is a reason others haven't taken this idea and run with it? Is it because it doesn't really fit Thief? I'm giving a huge thumbs up for the effort and thinking outside the box, but a very low score for how it looks to the player and how confusing and, honestly, ugly the custom screens were.

IMHO, the demo here is on the custom screens and choosing a character loadout in-game. The rest was not helpful.